[MW:6104] MW:6101- Subsea Pipeline Testing

Limesh,

Det Norske Veritas(DNV) has a list of comprehensive guidelines/recommended practices on various offshore components, including pipelines.You may download these from :- http://exchange.dnv.com/publishing/Codes

The following standards would be quite useful:-

DNV-OS-F101-SUBMARINE PIPELINE SYSTEMS-This standard gives criteria and guidance on concept development, design, construction, operation and abandonment of Submarine Pipeline Systems

DNV-RP-F116-INTEGRITY MANAGEMENT OF SUBMARINE PIPELINE SYSTEMS- provides requirements, as given in DNV-OS-F101 and recommendations for managing the integrity of submarine pipeline systems during the entire service life.

Usually for new offshore piping fabrication design, welding, NDT ,inspection criteria are far more stringent than onshore piping( at least as per DNV practices).See the sample below.

For pipelines in service, the integrity/life management program is the key. RP-F-116 explains various concepts behind life management program.

Most common construction guideline for such pipelines is API RECOMMENDED PRACTICE 1111-Design, Construction, Operation,and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design). As per this RP, hydro test should be done pipelines as follows:-

all parts of an offshore pipeline designed according to this RP should be subjected to an after-construction strength test of not less than 125% of the pipeline maximum operating pressure. Flow lines and flow line risers should be subjected to hydro test of 125% of the MOP; or 111% of shut in pressure whichever is greater. Hydro test should not result in combined loads exceeding 96% of capacity.

The version of API I referred to is a bit old (2000). I am sure there had been a lot of changes in recent years. If the others have reference to the new version of API RP 1111, it would be appreciated.

Thanks.

Pradip Goswami,P.Eng.
Welding & Metallurgical Engineer/Specialist
Ontario Power Generation Inc.
Email-pgoswami@sympatico.ca,
pgoswami@quickclic.net

-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of limesh M
Sent: Friday, July 23, 2010 12:44 PM
To: Materials & Welding
Subject: [MW:6101] Subsea Pipeline Testing

Dear All,

How welding quality is assured in subsea pipe lines? Is it necessary to hydrotest these lines? If yes then what is the procedure & how leaks (if any) are identified? Any code designed for this?

Thanks and Regards,

Limesh

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